A 2025 study published in Current Biology reports the first documented use of tools by marine mammals. Scientists have been studying three pods of killer whales, also known as orcas, in the Pacific Northwest for decades. Using unmanned drones, they observed the whales biting off the stalk ends of bull kelp and using them as tools to massage and scrub each other’s bodies—an activity scientists call allokelping. Thirty sightings of this activity among three pods were documented over the span of 12 days, involving different ages and sexes. The scientists believe allokelping may be a form of social, tool-assisted skin grooming. They also hypothesize that the behavior is unique to this killer whale society.